A 0.750 kg block is attached to a spring with spring constant 17.5 N/m. While the block is sitting at rest, a student hits it with a hammer and almost instantaneously gives it a speed of 39.0 cm/scm/s . What are:

a. The amplitude of the subsequent oscillations?
b. The block's speed at the point where x= 0.750 A?

Respuesta :

Answer:

a

 [tex]A = 0.081 \ m[/tex]

b

The value is  [tex]u = 0.2569 \ m/s[/tex]

Explanation:

From the question we are told that

   The mass is  [tex]m = 0.750 \ kg[/tex]

   The spring constant is  [tex]k = 17.5 \ N/m[/tex]

    The instantaneous speed is  [tex]v = 39.0 \ cm/s= 0.39 \ m/s[/tex]

    The position consider is  x =  0.750A  meters from equilibrium point

   

Generally from the law of  energy conservation we have that

        The kinetic energy induced by the hammer  =  The energy stored in the spring

So

          [tex]\frac{1}{2} * m * v^2 = \frac{1}{2} * k * A^2[/tex]

Here a is the amplitude of the subsequent oscillations

=>      [tex]A = \sqrt{\frac{m * v^ 2 }{ k} }[/tex]

=>      [tex]A = \sqrt{\frac{0.750 * 0.39 ^ 2 }{17.5} }[/tex]

=>       [tex]A = 0.081 \ m[/tex]

Generally from the law of  energy conservation we have that

The kinetic energy  by the hammer  =  The energy stored in the spring at the point considered   +   The kinetic energy at the considered point

             [tex]\frac{1}{2} * m * v^2 = \frac{1}{2} * k x^2 + \frac{1}{2} * m * u^2[/tex]

=>          [tex]\frac{1}{2} * 0.750 * 0.39^2 = \frac{1}{2} * 17.5* 0.750(0.081 )^2 + \frac{1}{2} * 0.750 * u^2[/tex]

=>          [tex]u = 0.2569 \ m/s[/tex]